A Michigan woman is charged with mutilating and illegally removing a corpse after her 32-year-old son's body parts were found in bags along two rural roadways in the US.

Donna Scrivo petitioned Macomb County's probate court last May for "temporary guardianship on an emergency basis because her son was suicidal and despondent over the illness of his father", who later died, Probate Judge Carl Marlinga said.

"The original hearing had two clinical certificates from doctors stating he did suffer from psychosis and that he was a danger to himself, and that he had expressed suicidal thoughts," Marlinga said. "There was obviously sufficient evidence to consider emergency guardianship.

"He consented to having a guardian appointed and his preference that it would be his mother."

Marlinga was not involved in the criminal case against Donna Scrivo, who was arraigned on Monday (local time) in St Clair Shores District Court.

The mutilation charge is a felony carrying up to 10 years in prison upon conviction. The second charge, removing a body from the place where death occurred, is a one-year misdemeanour.

Prosecutors said Ramsay Scrivo's mother filed a missing person's report on January 27, claiming he had left his St Clair Shores home and failed to return.

Three days later, someone reported seeing a woman dumping trash bags from an SUV along roadsides in China and St. Clair townships in St Clair County, about 80 kilometres northeast of Detroit.

Police found body parts inside the bags. The FBI later identified the body as belonging to Ramsay Scrivo through fingerprints.

A cause of death has not been released.

Surveillance video from a business near where the bags were found showed Donna Scrivo was in the area at the time, a prosecutor said during her arraignment on Monday.

A search of the man's home in St. Clair Shores found "blood evidence" and "bleach stains", the prosecutor said.

District Judge Mark Fratarcangeli on Monday ordered Donna Scrivo held on US$100,000 (NZ$123,000) bond and said he would appoint an attorney for her. Her next court date is February 11. A preliminary hearing is scheduled for February 14.